Steam traps are small, inexpensive valves that do a big job: they let condensate and air out of a steam system while keeping live steam in. When a trap fails, nobody notices right away. But a facility with hundreds of traps and no testing program almost always has a share of them failed open, blowing steam, or failed closed, backing up condensate.
What happens when a trap fails
Failed open (blowing through). Live steam passes straight into the condensate return. The boiler makes steam that does no useful work. Signs include:
- Steam plumes from condensate vents or receivers
- Condensate return lines that are hotter than normal
- Higher fuel use without a change in production
Failed closed (plugged). Condensate cannot drain. It backs up into the equipment or steam main. Signs include:
- Heat exchangers, coils or process equipment that heat slowly
- Water hammer (banging in steam lines)
- Cold traps or cold sections of pipe downstream of equipment
Water hammer is more than noise. Slugs of condensate moving at steam velocity can damage valves, fittings and gaskets, and can cause dangerous failures.
How steam traps are tested
A good trap survey combines several methods:
- Ultrasonic testing listens to the flow through the trap to tell normal cycling from continuous blow-through.
- Temperature measurement with an infrared thermometer or contact probe shows whether a trap is cold (plugged) or hot on both sides.
- Visual checks at test valves or open discharges, where they exist.
Each trap gets a tag, a location and a recorded condition. That list becomes your repair plan and your baseline for the next survey.
How often to survey
High-pressure and process-critical traps are often checked more frequently than low-pressure heating traps. Many facilities survey at least once a year, and more often for critical equipment. Your operating conditions and history should set the schedule.
Repair or replace?
Some trap types can be rebuilt with a repair kit. Others are cheaper to replace. While you are at it, check that the trap type fits the application. A trap that keeps failing is often the wrong type or size for the load.
Traps and the boiler
Failed traps affect the boiler room directly. Blow-through raises steam demand and fuel use. Plugged traps and poor condensate return mean more cold makeup water, which brings more dissolved oxygen and minerals into the boiler. That raises the load on your water treatment and deaerator.
Need help with your steam system?
Boilers on Demand services industrial steam boilers and systems throughout the Houston area, including the Ship Channel and petrochemical corridor. Our boiler repair team can troubleshoot steam system problems, and if your plant needs steam while repairs happen, we offer rental boilers. Read more about the top causes of boiler downtime, or call 936-300-4111.
